With the current widespread use of smartphones, the increase in data traffic in a cellular system becomes an issue. Thus, the increase in communication channel capacity in a cellular system is increasingly important for mobile network operators.
In order to increase the communication channel capacity, for example, mobile network operators deploy a small cell such as picocell and femtocell within a macrocell. In other words, mobile network operators employ heterogeneous network deployment. This deployment enables the mobile network operators to achieve larger communication channel capacity through a cell-splitting gain. However, in such a heterogeneous network, interference may occur between a small cell and a macrocell, and thus a technique to prevent the occurrence of interference between a small cell and a macrocell has been studied.
For example, Patent Literature 1 discloses a technology that prevents the occurrence of interference by adjusting appropriately transmission power of terminals and a base station using a cooperation manager when the frequency spectrum is shared between a small cell and a macrocell in a heterogeneous network.